/*
* Conditions Of Use
*
* This software was developed by employees of the National Institute of
* Standards and Technology (NIST), an agency of the Federal Government.
* Pursuant to title 15 Untied States Code Section 105, works of NIST
* employees are not subject to copyright protection in the United States
* and are considered to be in the public domain.  As a result, a formal
* license is not needed to use the software.
*
* This software is provided by NIST as a service and is expressly
* provided "AS IS."  NIST MAKES NO WARRANTY OF ANY KIND, EXPRESS, IMPLIED
* OR STATUTORY, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTY OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, NON-INFRINGEMENT
* AND DATA ACCURACY.  NIST does not warrant or make any representations
* regarding the use of the software or the results thereof, including but
* not limited to the correctness, accuracy, reliability or usefulness of
* the software.
*
* Permission to use this software is contingent upon your acceptance
* of the terms of this agreement
*
* .
*
*/
package gov.nist.javax.sip.parser;
import gov.nist.javax.sip.header.*;
import gov.nist.core.*;
import java.text.ParseException;
import javax.sip.*;

/**
 * Accept-Encoding SIP (HTTP) Header parser.
 *
 * @version 1.2 $Revision: 1.7 $ $Date: 2009-07-17 18:57:56 $
 *
 * @author Olivier Deruelle
 * @author M. Ranganathan
 *
 *
 * <pre>
 *
 *   The Accept-Encoding request-header field is similar to Accept, but
 *   restricts the content-codings (section 3.5) that are acceptable in
 *   the response.
 *
 *
 *       Accept-Encoding  = "Accept-Encoding" ":"
 *                      ( encoding *( "," encoding) )
 *       encoding         = ( codings *[ ";" "q" "=" qvalue ] )
 *       codings          = ( content-coding | "*" )
 *
 *   Examples of its use are:
 *
 *       Accept-Encoding: compress, gzip
 *       Accept-Encoding:
 *       Accept-Encoding: *
 *       Accept-Encoding: compress;q=0.5, gzip;q=1.0
 *       Accept-Encoding: gzip;q=1.0, identity; q=0.5, *;q=0
 * </pre>
 *
 */
public class AcceptEncodingParser extends HeaderParser {

    /**
     * Constructor
     * @param acceptEncoding message to parse
     */
    public AcceptEncodingParser(String acceptEncoding) {
        super(acceptEncoding);
    }

    /**
     * Constructor
     * @param lexer Lexer to set
     */
    protected AcceptEncodingParser(Lexer lexer) {
        super(lexer);
    }

    /**
     * parse the String message
     * @return SIPHeader (AcceptEncoding object)
     * @throws ParseException if the message does not respect the spec.
     */
    public SIPHeader parse() throws ParseException {
        AcceptEncodingList acceptEncodingList = new AcceptEncodingList();
        if (debug)
            dbg_enter("AcceptEncodingParser.parse");

        try {
            headerName(TokenTypes.ACCEPT_ENCODING);
            // empty body is fine for this header.
            if (!lexer.startsId()) {
                AcceptEncoding acceptEncoding = new AcceptEncoding();
                acceptEncodingList.add(acceptEncoding);
            } else {
                do {
                    AcceptEncoding acceptEncoding = new AcceptEncoding();
                    if (lexer.startsId()) {
                        Token value = lexer.match(TokenTypes.ID);
                        acceptEncoding.setEncoding(value.getTokenValue());

	                    while (lexer.lookAhead(0) == ';') {
	                        this.lexer.match(';');
	                        this.lexer.SPorHT();
	                        Token pname = lexer.match(TokenTypes.ID);	// JvB Also allows generic param!
	                        this.lexer.SPorHT();
	                        if ( lexer.lookAhead() == '=' ) {
	                        	this.lexer.match('=');
	                        	this.lexer.SPorHT();
	                        	value = lexer.match(TokenTypes.ID);
	                        	if ( pname.getTokenValue().equalsIgnoreCase("q")) {
			                        try {
			                            float qv = Float.parseFloat(value.getTokenValue());
			                            acceptEncoding.setQValue(qv);
			                        } catch (NumberFormatException ex) {
			                            throw createParseException(ex.getMessage());
			                        } catch (InvalidArgumentException ex) {
			                            throw createParseException(ex.getMessage());
			                        }
	                        	} else {
	                        		acceptEncoding.setParameter( pname.getTokenValue(), value.getTokenValue() );
	                        	}
		                        this.lexer.SPorHT();
	                        } else acceptEncoding.setParameter( pname.getTokenValue(), "" );
	                    }
                    }
                    acceptEncodingList.add(acceptEncoding);
                    if (lexer.lookAhead(0) == ',') {
                        this.lexer.match(',');
                        this.lexer.SPorHT();
                    } else break;
                } while (true);
            }
            return acceptEncodingList;
        } finally {
            if (debug)
                dbg_leave("AcceptEncodingParser.parse");
        }
    }
}
/*
 * $Log: not supported by cvs2svn $
 * Revision 1.6  2006/07/13 09:02:03  mranga
 * Issue number:
 * Obtained from:
 * Submitted by:  jeroen van bemmel
 * Reviewed by:   mranga
 * Moved some changes from jain-sip-1.2 to java.net
 *
 * CVS: ----------------------------------------------------------------------
 * CVS: Issue number:
 * CVS:   If this change addresses one or more issues,
 * CVS:   then enter the issue number(s) here.
 * CVS: Obtained from:
 * CVS:   If this change has been taken from another system,
 * CVS:   then name the system in this line, otherwise delete it.
 * CVS: Submitted by:
 * CVS:   If this code has been contributed to the project by someone else; i.e.,
 * CVS:   they sent us a patch or a set of diffs, then include their name/email
 * CVS:   address here. If this is your work then delete this line.
 * CVS: Reviewed by:
 * CVS:   If we are doing pre-commit code reviews and someone else has
 * CVS:   reviewed your changes, include their name(s) here.
 * CVS:   If you have not had it reviewed then delete this line.
 *
 * Revision 1.3  2006/06/19 06:47:27  mranga
 * javadoc fixups
 *
 * Revision 1.2  2006/06/16 15:26:28  mranga
 * Added NIST disclaimer to all public domain files. Clean up some javadoc. Fixed a leak
 *
 * Revision 1.1.1.1  2005/10/04 17:12:35  mranga
 *
 * Import
 *
 *
 * Revision 1.4  2004/01/22 13:26:31  sverker
 * Issue number:
 * Obtained from:
 * Submitted by:  sverker
 * Reviewed by:   mranga
 *
 * Major reformat of code to conform with style guide. Resolved compiler and javadoc warnings. Added CVS tags.
 *
 * CVS: ----------------------------------------------------------------------
 * CVS: Issue number:
 * CVS:   If this change addresses one or more issues,
 * CVS:   then enter the issue number(s) here.
 * CVS: Obtained from:
 * CVS:   If this change has been taken from another system,
 * CVS:   then name the system in this line, otherwise delete it.
 * CVS: Submitted by:
 * CVS:   If this code has been contributed to the project by someone else; i.e.,
 * CVS:   they sent us a patch or a set of diffs, then include their name/email
 * CVS:   address here. If this is your work then delete this line.
 * CVS: Reviewed by:
 * CVS:   If we are doing pre-commit code reviews and someone else has
 * CVS:   reviewed your changes, include their name(s) here.
 * CVS:   If you have not had it reviewed then delete this line.
 *
 */
